State-of-the-art apparatuses for transferring liquid helium comprise metal connections constituted by two co-axial tubes, an internal tube conveying the liquid helium and an external tube supporting a vacuum, to provide thermal insulation for the liquid-helium-conveying internal tube.
The internal and external tubes are connected to endpieces by vacuum-tight welds.
State-of-the-art apparatuses for transferring liquid helium do not enable liquid helium to be supplied to cryogenic installations which are connected to high voltage, from a reservoir or a condenser for helium which is connected to ground.